Just remember that that probably means that they are DYING. They are in their death throes. That last spasm. Although, it sure doesn't feel like it, does it?
One thing I told myself to make me feel better was that it wasn't actually the parasites themselves doing the flib-flubbing, that the chemicals they release when they die make my muscles contract. I totally made that up, there is no truth to it that I know, but I cling to that tiny possibility every time my guts spaz out like they have the past few days.
Sometimes, only sometimes, ignorance is bliss if it gets you through the night.